A market exists for fuels developed for application with cooking, catering, use in high-end kitchens for specific applications and for use in conjunction with banquets.
One such fuel which is quite common is Sterno®, produced by Sterno Group LLC which as of October 2012 is a subsidiary of Candle Lamp Company LLC, and typically sold in tins with tightly pressed lids sized to fit beneath a chafing dish or in another such receptacle for use in cooking (fondue, for example) or warming pre-cooked foods.
It is not uncommon to have many such chafing dishes in use during a buffet in a restaurant for hours at a time, or during an event where the meal service may last a duration requiring the use of refills of these tins to continue to warm food which may also be continually replenished for selection and consumption by the customers or attendees.
Common considerations which must be taken into account include:
adequate ventilation, as byproducts of combustion are released into the venue and present potential risk to the health of those exposed to it;
temperature, as the correct temperature is directly responsible for keeping the food being warmed at the right temperature not only for pleasurable consumption, but also to inhibit the growth of potentially harmful bacteria;
rate of combustion, as the consumption rate of the fuel determines how many times the tins must be replaced;
portability, as the volatility and transportability affect the transport and use of the fuel in a public and consumer-rich environment;
residual taste; and
cost, which is always of concern as fuel costs rise and fall according to the laws of supply and demand, and in the case of ethanol, has experienced some market volatility depending on where and how the ethanol base has been generated.
These gel-type fuels typically contain several major constituents, a base fuel such as an alcohol, a nontoxic denaturant, a thickening agent and in some cases, pH balancers and other chemicals.
In the case of ventilation, it is important to have as clean burning a fuel as possible. Carbon based fuels contain harmful byproducts of combustion including CO2, water and CO, carbon monoxide, potentially fatal to humans if inhaled instead of air. Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. A psychoactive drug and one of the oldest recreational drugs known, ethanol produces a state known as alcohol intoxication when consumed. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a solvent, and as a fuel. In common usage, it is often referred to simply as alcohol or spirits. Ethanol is already being used extensively as a fuel additive, and the use of ethanol fuel alone or as part of a mix with gasoline is increasing. Compared to methanol its primary advantage is that it is less corrosive and additionally the fuel is non-toxic, although the fuel will produce some toxic exhaust emissions. Ethanol combustion is: C2H5OH+3O2→2CO2+3H2O+heat.
As can be seen, water and carbon dioxide comprise the byproducts of ethanol combustion, removing the risk of exposure to carbon monoxide by humans.
By employing ethanol as the base fuel in a gel-type fuel application for use in the restaurant and banquet arena, a safer and more public consumption friendly medium can be used.
One liter of ethanol contain 21.1 MJ, a liter of methanol 15.8 MJ and a liter of gasoline approximately 32.6 MJ. In other words, for the same energy content as one liter or one gallon of gasoline, one needs 1.6 liters/gallons of ethanol and 2.1 liters/gallons of methanol. The raw energy-per-volume numbers produce misleading fuel consumption numbers however, because alcohol-fueled engines can be made substantially more energy-efficient. A larger percentage of the energy available in a liter of alcohol fuel can be converted to useful work. This difference in efficiency can partially or totally balance out the energy density difference depending on the particular engines being compared.
Therefore, in the case of temperature, it is clear that ethanol provides plenty of ready energy for the rather benign function (comparatively speaking) of gently cooking or warming food. With the elimination of more toxic combustion byproducts, alcohol based fuel are well suited for the intended application.
With respect to rate of consumption, the formulation of the gel or thickening agent of the fuel in combination with the ratio of alcohol to water or other denaturant dictates the amount of release of available alcohol for burning.
Considering the factor of portability and other uses for alcohol based fuels, depending on the type of gelling or thickening agent used, different applications for the fuel may be realized.
In the United States, alcohol must be “denatured” to a quality that is non-beverage grade. This is accomplished by using a denaturant. This results also in the alcohol being exempted from taxes under the U.S. Treasury Department, Tax and Trade Bureau (“TTB”) regulations. Several denaturants may be employed to satisfy these criterion and regulations.
Dorries et al. US Pub. No. US 2010/0186286 A1 Jul. 29, 2010, discloses a fuel gel including an alcohol, a nontoxic denaturant, a thickening agent, and at least one neutralizing agent. Primarily the formulation involves ethanol, denatonium benzoate, acrylic acid homopolymers, diisopropanolamine, corn-based glycerin and distilled water. As such, the use of what is essentially alcohol means that the fuel may derive from many sources such as methanol, meaning many variations also affecting overall fuel performance. and
Merdjan et al. U.S. Pub. No. US 2003/0217504 A1 Nov. 27, 2003 discloses a fuel medium in a gel state consisting entirely of material from vegetable matter in combination with alcohol, primarily ethanol, and water. Methyl Hydroxylpropyl Cellulose MHPC is employed to create the gel.
While Merdjan strives to use entirely materials from vegetable matter as constituents in the fuel, the objective of using a more or less fully “organic” approach puts that approach above that of fuel efficiency, burning or consumption rate. Using vegetable matter produces less heat and does not provide sufficient control of burn time. The Dorries reference discloses a large number of constituents in several steps which result in a complex fuel with characteristics dictated thereby.
What is needed then is a fuel with the benefits associated with a sustainable and renewable fuel, with the desired burn rate and heat output.
Further, what is needed is a process which is easily followed with simple steps and which produces a clean burning fuel being the most desirable for use in connection with food service.
While many of these gel-type fuels have a basic formula, they are not necessarily suited for variations in the formulae which allow different functions, such as flowability for use as a refill for the original packaging. Nor does the prior art disclose nearly equivalent formulae for creating a more liquid fuel which can be even more flowable to be used as an ingniter for common uses in the food industry.
What is needed then is a formulaic base having multiple functions available by way of thickening or thinning such that the fuel may be used in chafers, as a flowable, effective refill for use in original or dedicated receptacles and as a more or less free-flowing fuel for use in igniting charcoal, for example, functions not found in the prior art of gel-type fuels.
The last criterion which separates superior products from ordinary fuels in the food service business is the factor of taste and smell. Having a fuel with effectively no adverse affect on taste or smell of the food is the differential between success and potential failure. Residual smells (also the basis of taste) from constituent of the fuel must be managed by either minimization, selection or avoidance.
What is needed then is a fuel having all the favored performance discussed herein including in addition, the elimination of effects of combustion manifest in taste and smell imparted to the food.